Your Sodium Level: What's Normal, What's Not

Salt often gets a bad rap when it comes to your health. But you need it to function, which is why having normal sodium levels can help your body work at its best.

Maintaining a normal sodium level in the blood has less to do with the amount of salt you eat and more to do with your hydration. Below, learn about the signs your sodium levels are off and what to do to correct them.

The Mayo Clinic defines a normal sodium level range as 135 to 145 milliequivalents per liter, which is a measure of the concentration of sodium in your blood. Levels that fall above or below sodium's normal range are typically the result of over- or under-hydration, according to a March 2015 review in ‌American Family Physician‌, rather than eating too little or too much salt.

Sodium is a type of electrolyte, which is a class of minerals that conduct electrical signals to your nerves and muscles to help your body function, according to the U.S. National Library of Medicine (NLM).

Sodium in particular helps balance the amount of fluid in your body and manage blood pressure, muscle control and nerve function, per the National Kidney Foundation. It works closely with other electrolytes, like potassium, to do this, according to the NLM.

For healthy adults who don't have any kidney problems, "the kidneys do an amazing job at keeping us at the proper hydration level, which includes sodium," Jen Hernandez, RDN, CSR, a registered dietitian-nutritionist and board-certified specialist in kidney nutrition, tells LIVESTRONG.com.

But abnormal sodium levels can lead to unpleasant symptoms. If your doctor suspects your sodium balance is off, they can check with a standard blood draw, which is often a part of your routine physical.

Signs of low sodium — also called hyponatremia — include the following, per the NLM and a January 2021 StatPearls review:

• Weakness
• Fatigue
• Confusion
• Headaches
• Nausea
• Vomiting
• Malaise
• Muscle cramps or spasms
• Agitation

Sometimes symptoms of hyponatremia in older adults can be confused with those of age-related neurological conditions like dementia or Alzheimer's disease. Monitoring fluid intake and cognitive status can help determine whether hydration is to blame for chronic symptoms of low sodium in older adults.

In extreme cases, very low sodium levels can deplete your brain of electrolytes, which leads to brain swelling, seizures or coma, according to a January 2018 study in ‌Kidney International Reports‌. This requires immediate medical attention to restore your fluid and electrolyte balance.

Here are several common reasons why your sodium levels can dip:

"Some may think a low sodium level in the blood is related to inadequate sodium intake in the diet," Hernandez says. "But that is almost always not the case."

In fact, the most common cause of low sodium levels is over-hydration. Hernandez says the amount of water in your body can dilute your sodium levels to the point of hyponatremia: For instance, this can happen when endurance athletes like marathon runners water down their blood sodium content by drinking more than they need to quench their thirst.

Luckily, recovery from mild effects of low sodium is typically quick, according to the Mayo Clinic. Symptoms should resolve as soon as the root cause — too much fluid — is fixed, which you can address by temporarily reducing how much you drink. Sometimes doctors will also prescribe a diuretic to help rid the body of some excess fluid, Hernandez says.

Persistently low sodium levels, however, can be a side effect of certain medications like diuretics, according to StatPearls.

Diuretic medications (aka water pills) are often prescribed to help control high blood pressure, according to the Mayo Clinic, and they may also be taken by people who have edema (tissue swelling), heart failure, liver failure or certain kidney disorders, such as kidney stones.

You can work with your doctor to monitor medications that may mess with your sodium balance so you can stay on top of your hydration.

Hyponatremia is also more common in people who have chronic kidney, liver, heart or lung problems, per the Cleveland Clinic.

Low sodium levels can likewise be an issue for people who have cancer as a result of treatment or the disease itself, according to a June 2016 review in ‌Critical Reviews in Hematology/Oncology.‌

Hyponatremia can be a bigger problem for older than younger adults.

According to a November 2017 study in ‌Clinical Interventions in Aging‌, causes of low sodium in older adults include:

• Changing hormones
• Chronic illnesses like heart failure and liver disease
• Side effects from common medications like diuretics or antidepressants

The best way to increase sodium levels in older adults is much the same as the young: The same study notes that restricting water intake, intravenous (IV) fluids and stopping any drugs that might be contributing to low sodium levels can all help.

On the other hand, high sodium levels — or hypernatremia — can be a sign of dehydration. The Mayo Clinic and a May 2021 StatPearls review cite these common symptoms:

• Excessive thirst
• Decreased ability to urinate
• Nausea
• Vomiting
• Fatigue
• Dizziness
• Confusion

In serious cases, this electrolyte imbalance can lead to seizures or comas, according to a January 2016 study in the ‌Journal of Clinical Neurology‌.

The following reasons may be to blame for elevated sodium levels:

Hypernatremia usually occurs as a result of simply not drinking enough fluid, according to the NLM. It's especially common in infants, children and older adults, who may have more difficulty keeping themselves hydrated and are more susceptible to losing fluids through illness, according to the Mayo Clinic.

A quick fix? Drink more water, according to the Mayo Clinic. In the case of more extreme hypernatremia, your doctor may also give you IV fluids to help you get back into balance.

You can also quickly lose too much fluid from excessive sweating, according to the Mayo Clinic. As a result, athletes and anyone participating in intense exercise are at risk for hypernatremia.

To avoid it, be sure to consume enough fluids during heavy activity. If you're participating in prolonged intense exercise, like a marathon or triathlon, the Cleveland Clinic recommends also replenishing with sodium supplements like sports drinks to keep your salt balance from swinging too far in the opposite direction.

If you're sick with symptoms like vomiting and diarrhea, you can lose too much fluid too quickly and end up with hypernatremia, according to the Centers for Disease Control and Prevention (CDC).

Make sure to stay well-hydrated as long as symptoms persist to compensate for that fluid loss. If drinking water is difficult due to vomiting, try sucking on ice chips.

You may need to hydrate more than usual if you live in a hot climate or work outside, according to the CDC, as you may be more prone to losing fluids through sweat than people in cooler environments.

The solution? Keep an eye on your hydration to make sure your blood sodium levels don't spike. One easy way to keep track is by looking at the color of your urine: It should be clear to pale yellow if you're hydrated; darker yellow urine is a sign of dehydration.

Persistent hypernatremia can be a sign of kidney problems or adrenal gland disorders like Addison's disease, per the Mayo Clinic, both of which can impair the body's ability to regulate sodium levels.

Uncontrolled diabetes or a rare condition called diabetes insipidus can also lead to hypernatremia, according to an October 2014 study in the ‌World Journal of Clinical Cases‌.

If you suspect you have any of the above conditions, see your doctor, who can determine a diagnosis and help you manage the condition.